Method for punching acoustical tile



y 1966 P. F. SCHNEIDER 3,248,977

METHOD FOR PUNCHING ACOUSTICAL TILE Original Filed Feb. 24, 1959 2 Sheets-Sheet l INVENTOR PAUL E SCHNEIDER ATTORNEY May 3, i966 P. F. SCHNEIDER 3,

METHOD FOR PUNCHING ACOUSTICAL TILE Original Filed Feb. 24, 19 59 3 Sheets-Sheet 2 INVENTOR PAUL F. SCHNEIDER ATTORNEY United States Patent 3,248,977 METHOD FOR PUNCHING ACOUSTICAL TILE Paul F. Schneider, Lancaster County, Pa., assignor to Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Original application Feb. 24, 1959, Ser. No. 795,202. Divided and this application Feb. 10, 1965, Ser. No. 431,679

2 Claims. (Cl. 832) This is a division of my copending U.S. patent application Serial No. 795,202, filed February 24, 1959, now abandoned.

This invention relates to a method for perforating fibrous sheet material and more particularly to a method for punching openings in fibrous sheet material to expose the interior fibrous mass of said material for the admission and absorption of sound waves to improve the acoustical properties of the material.

In the production of acoustical tile for sound treatment of rooms, etc., it has been common practice to manufacture a fiberboard of relatively low density from mineral fibers or vegetable fibers and to open the surface of such board to permit sound waves to enter through the openings and become entrapped in the interstices occurring between the fibers in the board. One of the early acoustical tiles of this type was made of wood fiber, and the openings were provided by drilling holes in the tile for a substantial depth. Because of certain limitations arising from the mechanical equipment used to drill such holes, it was necessary to have holes of substantial diameter usually ranging from 7 to in diameter. The material so made had a plurality of holes arranged in straight rows from one edge of the tile to the other. Sales of these tiles were usually made by acoustical contractors through architects for large installations such as schools,

churches, hospitals, office buildings, etc. Because of this somewhat limited usage, the tiles having the straight row hole arrangement were generally considered to have an institutional appearance.

The need for a fireproof acoustical tile brought about the development of a fissured mineral fiber acoustical tile in whch a wet slurry of mineral fibers and a suitable binder such as starch is prepared on a board-forming machine, and the fissuring is accomplished by pulling apart the surface of the material, forming fissures between adjacent clumps of fibers. This material has the general appearance of travertine stone which is pleasing and considered highly desirable as a building material from an aesthetic standpoint. Because of the higher cost of the raw material used in this type of tile it is more expensive than that made from wood fibers.

Recent trends in home building and remodeling have been toward the use of acoustical materials on the ceilings of homes in such places as recreation rooms, kitchens, etc., and extensive development work has been done to perfect materials having surface appearances suitable for use in private homes at a cost within the range of materials used in home construction and remodeling. One of the first departures from the straight row institutional look tile was the so-called skip random pattern in which a conventional straight row drill jig was used, removing certain drills entirely and alternating different size drills in the remaining spaces, providing a pattern in which a limited number of drilled holes is present, arranged in straight lines with certain blank areas in which there were no holes.

The next development was the full-random pattern in which the holes were arranged in a haphazard manner devoid of any straight line arrangement. Both of these patterns were limited to the type of hole that was formed 'ice tile simulating the appearance of the more expensive fissured mineral fiber acoustical tile. Also in the mineral fiber tile it was felt desirable to utilize a method of fissuring in which a controlled pattern could be produced to lend a more uniform appearance to the ceiling on which it was installed. Also by controlling the positioning of the fissures, stronger edges are obtainable on the tile because there is no likelihood of a fissure occurring in the cut edge as is possible in the pulled wet fissuring process.

It has been found that desirable pattern characteristics of acoustical tiles can be obtained by punching small holes in the material. One typical design which has met with considerable commercial success is the fissure design simulating the fissure design of mineral fiber tiles in which certain punches punch out areas of the board simulating the fissures which heretofore had been pulled in the mineral fiber tile while in the wet state and which occur naturally in travertine. In addition to these fissure openings which permit sound waves to enter the fiber structure of the tile, it has been found desirable to perforate or punch the flat areas of the tile to more closely simulate the apearance of travertine. The method of producting this type of material is disclosed in pending patent application Serial No. 666,406 in the names of Milton G. Brown and Robert C. Philippi, filed June 18, 1957, now Patent No. 3,013,626.

Other appealing patterns have resulted from the use of various sized punches making small round openings differing in diameter from one to the other. Because the punches can be spaced more closely to one another than the rotating drills which must be attached to a device for rotating them, many more punches can be used placing many more openings in the material, but the size of the openings is such that they are not readily seen by a casual observation, giving an appearance of a pleasing texture rather than bold holes as in the drilled type. Also the use of punches makes available a greater percentage of the interior mass of the fibrous material for sound absorption purposes.

One of the problems involved in punching fiberboard to obtain the fissure pattern referred to above arises from the fact that the smaller holes are close to the fissures, and if the fissure punches and hole punches are both carried by the same punch plate and are forced into the board on one punching operation, the surface of the tile tends to collapse. To overcome this the punching operation must be carried out in two steps. Also in those patterns where a large number of small holes is positioned in close by drilling, and the industry recognized the desirability of producing a relatively inexpensive wood fiber acoustical proximity to one another, the surface of the board collapses if all the holes are punched at one time. In producing this type pattern it is desirable to punch one set of holes with one punching step and produce the intermediate holes by a second punching step.

In order to perform this punching operation the prior practice has been to employ two punch plates, and the design is punched in the board on two separate punching operations. One plate puts approximately one-half of the openings in the board, and the second plate puts the other half of the openings in the board. This system presents the problem of registering to make certain that the previously punched tile are properly positioned for the second punching step. In the high speed equipment used to produce this material, this is a difficult problem.

By practicing the method of this invention it is possible to punch all of the openings in agiven piece of material on one stroke of a double-action punch press regardless of the pattern involved, whether it be the fissure and hole design or a multiplicity of different sized holes. In the equipment used in carrying out this method the one set of punches is positioned on a plate, and the second set of punches is attached to a superimposed plate with the punches carried thereby operating through openings in the first punch plate. The piece of tile being punched remains in one position during the entire punching operation, and the problem of registry is removed because the punches are previously aligned and maintain such alignment.

An object of this invention is to provide a method whereby acoustical tile having a multiplicity of openings positioned in close proximity to one another in the surface thereof can be produced on a single stroke of a double-action punch press.

In order that the invention may be more readily understood it will be described in connection with the attached drawing in which FIGURE 1 shows a front elevational view of the device used for carrying out the invention;

FIGURE 2 is a cross-section showing the relative positions of the parts;

FIGURE 3 is a view of the bottom of the punch plate;

FIGURE 4 shows one pattern of surface treatment obtainable by this method and apparatus; and

FIGURE 5 shows a modified pattern.

Referring to the drawing, there is shown a press ram 2 which carries the entire device for carrying out the method herein disclosed. The lower extremity of the press ram 2 broadens out to provide a holder 3 for the punch plate mechanism. Attached to the holder'3 is a punch holder plate 4 which is secured thereto by means of studs 5. The punches 6 are mounted on a plate 7 clamped between the holder 3 and the punch holder plate 4. The punch holder plate 4 is provided with openings through which the punches 6 pass, the punch holder plate 4 being of suflicient thickness to hold punches 6 straight. Positioned below the punch holder plate 4 is a punch stripper plate 8 attached by means of stripper bolts 9 to the punch holder plate 4. The stripper plate 8 is counter-bored at 10 to permit the stripper plate 8 to move vertically with respect to the punch holder plate 4. The punch stripper plate 8 also carries a punch plate 11 secured to its lower surface by means of studs 12. This punch plate 11 is provided with a plurality of punches 13. The punch plate 11 also carries a plurality of stripping pins 14 which operate against springs 15 carried in recesses 16 in the punch stripper plate 8. The punch stripper plate S'is also provided with a plurality of openings 17 through which the punches 6 pass freely.

Relative movement between the punch holder plate 4 and the stripper plate 8 is effected by hydraulic cylinders 18 and connecting rods 19. These connecting rods 19 are attached to the piston in the cylinders 18. The lower extremity of the connecting rods 19 is provided with engaging heads 20 which rest on the top surface of the holder 3. Rods 21 in alignment with connecting rods 19 pass freely through the holder 3, plate 7 and punch holder plate 4 and rest on the top surface of stripper plate8.

Hydraulic fluid under pressure is supplied to the cylinders 18 from an accumulator (not shown) through manifold 22 and inlet pipes 23 connecting the cylinders to the manifold. Any hydraulic fluid leaking past the piston in cylinders 18 is returned through lines 24 to return manifold 25 leading back to the accumulator. With this arrangement the cylinders are held under hydraulic pressure at all times during the operation of the device.

In the operation of the device, as the press ram 2 moves downwardly toward the work piece 26 positioned on the platen 27 therebeneath, the punches 13 carried by punch plate 11 are pushed into the surface of the board by the hydraulic pressure of the cylinder 18 acting on connecting rods 19 and aligned rods 21. Continued downward movement of the press ram 2 forces the punches 13 carried by the plate 11 into the surface of the board forming openings therein. As the punch plate 11 continues its downward movement, pins 14 engage the surface of the board and compress the springs 15 located in the .recesses 16 in the punch stripper plate 8. When the flat surface of punch plate 11 engages the surface of the board 26, the downward motion of the punch plate 11 ceases, however, the press ram 2 continues its downward 'movement carrying with it punch holder plate 4 and punches 6. The punches 6 pass freely through the openings 17 in the stripper plate 8 and the punch plate 11. Downward movement of the press ram 2 continues until the punches 6 enter the board to a sufficient depth.

Inasmuch as the hydraulic mechanism described earlier is mounted on the movable press ram 2 it moves with it. When downward motion of the punch plate 11 is halted by its engagement with the surface of board 26 the rods 21, connecting rods 19 and the piston in the cylinders 18 stop, but the cylinders 18 continue to move downwardly forcing hydraulic fluid through pipes 23 and manifold 22 to the accumulator. With the piston, connect-ing rods 19 and rods 21 stationary, continued downward movement of the press ram 2 causes engaging heads 20 to be positioned above the top surface of holder 3, exerting full force of the hydraulic pressure on the stripper plate 8. With this arrangement both the punches carried by the punch plate 11 and the punches carried by the punch holder plate 4 are now in the fiberboard to the desired extent.

Referring to FIGURE 3 there is shown the punch elements 13 which are elongated on a plane along the surface of the punch plate 11 to produce an irregular shaped opening in the surface of the tile simulating the appear ance of the fissures which occur naturally in travertine stone and which, prior to this invention, were pulled in the surface of fissured mineral fiber tile. Irregularly shaped openings 28 made by these elongated punches 13 are shown in FIGURE 4. The small holes 29 appearing in the tile of FIGURE 4 are produced by the punches 6 carried by the punch holder plate 4 which pass through the openings 17 in the stripper plate 8.

FIGURE 5 shows a pattern of two sizes of holes placed randomly in a piece of tile. In making a product of this type the holes of one size are produced by punches attached to punch plate 11 and the holes of the other size are produced by punches carried by punch plate 4 passing through stripper plate 8.

In the withdrawal stroke the punch press ram 2 starts in an upward direction carrying with it punch holder plate 4- and its punches 6. The pressure in the hydraulic system holds the stripper plate 8 in its down position with the surface of punch plate 11 in engagement with the face of the tile 26 while the punches 6 are being withdrawn therefrom, stripping the punched tile 26 from the punches 6. The stripper plate 8 remains in its down position until press ram 2 has moved upwardly a sufficient distance for the top surface of holder 3 to engage the engaging heads 20 in the bottoms of connecting rods 19. When this condition occurs the hydraulic pressure is exerted on the holder 3 instead of stripper plate 8.

When the engaging heads 20 engage the holder 3 the stripper bolts 9 have moved through the full length of the counter-bored portion of the stripper plate 8 so that the enlarged heads of the stripper bolts 9 engage the stripper plate 8 and move it along with the entire assembly. As the stripper plate 8 moves up, springs 15 expand forcing pins 14 outwardly stripping the tile 26 from the punches 13 carried by punch plate 11.

When press ram 2 reaches the top of its path of travel the cycle is repeated.

It has been found that the method herein disclosed can also be used to produce a fissured pattern in mineral fiber tile resulting in a controlled pattern effect rather than the haphazard effect produced by the pulling technique described as the prior art method of making this material.

In the specific embodiment here under consideration the punch head is made up to punch eight square feet of tile on one stroke as shown in FIGURE 3 thereby greatly increasing the speed with which material may be produced on a device of this type. In this embodiment four hydraulic cylinders 18 are employed for each square foot of tile or a total of thirty-two cylinders for the entire assembly.

It will be seen from this arrangement that the method disclosed herein is effective for putting two sets of openings in acoustical tile on a single stroke of the punch ram 2 and withdrawing the two sets of punches at different times thereby greatly diminishing the power required to operate the ram of the punch press.

I claim:

1. A method of producing artificial openings in acoustical material, the steps comprising placing a blank of material to be perforated in alignment with a reciprocating punch press head, forcing punches carried by one plate of said head into the surface of the blank and thereafter forcing punches carried by a second plate on said head into the surface of the blank while the first punches remain embedded therein, withdrawing the second set of punches from the blank while the first plate is in engagement therewith and thereafter withdrawing the first set of punches.

2. A method of producing artificial openings in acoustical material, the steps comprising placing a blank of material to be perforated in alignment with a reciprocating punch press head, forcing a set of punches carried by said head into the surface of the blank and while the blank remains in the same position forcing a second set of punches into the surface of the blank while the first set of punches remains embedded therein, and withdrawing the second set of punches from the blank while the first setis in engagement with the blank and thereafter withdrawing the first set of punches.

References Cited by the Examiner UNITED STATES PATENTS Re. 23,892 11/1954 Macewka 83-133 195,921 10/1877 Eaton 83133 2,352,339 6/1944 Olney 83618 2,355,454 8/1944 Lucius 832 WILLIAM W. DYER, IR., Primary Examiner.

ANDREW R. JUHASZ, Examiner. 

1. A METHOD OF PRODUCING ARTIFICIAL OPENINGS IN ACOUSTICAL MATERIAL, THE STEPS COMPRISING PLACING A BLANK OF MATERIAL TO BE PERFORATED IN ALIGNMENT WITH A RECIPROCATING PUNCH PRESS HEAD, FORCING PUNCHES CARRIED BY ONE PLATE OF SAID HEAD INTO THE SURFACE OF THE BLANK AND THEREAFTER FORCING PUNCHES CARRIED BY A SECOND PLATE ON SAID HEAD INTO THE SURFACE OF THE BLANK WHILE THE FIRST PUNCHES REMAIN EMBEDDED THERIN, WITHDRAWING THE SECOND SET OF PUNCHES FROM THE BLANK WHILE THE FIRST PLATE IS IN ENGAGEMENT THEREWITH AND AFTER WITHDRAWING THE FIRST SET OF PUNCHES. 